When a pull request introduces a dependency that triggers a Dependabot alert, it signifies a known vulnerability. The primary security principle is to prevent this vulnerability from being merged into the main codebase. The correct procedure is to update the dependency to a secure version within the feature branch itself. This action resolves the security risk before the code is integrated, aligning with the "shift left" security practice of addressing vulnerabilities early in the development lifecycle. Merging the pull request without this update would knowingly introduce a security flaw into the default branch.

A. Disable Dependabot alerts for all repositories owned by your organization: This action ignores the identified risk and weakens the overall security posture of the organization, leaving all repositories vulnerable.

B. Fork the branch and deploy the new fork: Forking the branch does not resolve the underlying vulnerability. Deploying code with a known vulnerability is insecure and counterproductive.

D. Deploy the code to your default branch: This is equivalent to merging the pull request with the known vulnerability, which directly contradicts the purpose of security scanning and introduces risk.

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1. GitHub Docs, "About Dependabot security updates." This document explains that Dependabot's purpose is to fix vulnerable dependencies. It states, "Dependabot security updates make it easier for you to fix vulnerable dependencies in your repository. If you enable this feature, when a Dependabot alert is raised for a vulnerable dependency in the dependency graph of your repository, Dependabot automatically tries to fix it by creating a pull request." This supports the principle of updating dependencies as the primary remediation step.

Source: GitHub Docs, Code security > Dependabot > Dependabot security updates > "About Dependabot security updates."

2. GitHub Docs, "About dependency review." This document describes how dependency review works on pull requests to prevent vulnerabilities from being introduced. It states, "Dependency review helps you understand dependency changes and the security impact of these changes at every pull request... you can prevent vulnerable dependencies from being added to your project." This directly supports resolving the issue within the pull request (Option C) before merging.

Source: GitHub Docs, Code security > Supply chain security > Understanding your software supply chain > "About dependency review."

3. GitHub Docs, "Viewing and updating vulnerable dependencies in your repository." This guide details the process for handling alerts, emphasizing that the resolution involves updating the package. It notes, "When you're ready to update the dependency... you can click the Dependabot alert to open the pull request that Dependabot has created to fix the vulnerability." This reinforces that the correct action is to update the dependency.

Source: GitHub Docs, Code security > Dependabot > Dependabot alerts > "Viewing and updating vulnerable dependencies in your repository."